The present invention relates to shutoff-opening devices comprising a valve main body and a plurality of valve actuators and fluid control apparatus comprising such devices.
The terms front, rear, upper, lower, right and left are herein used based on FIG. 2; the right-hand side, the left-hand side, the upper side and lower side of the drawing are referred to as front, rear, upper and lower, respectively, and the terms right and left are used for the device as it is viewed from the behind toward the front. The device may be used with the front-rear relationship as reversed, or the upper and lower side thereof positioned as the left and right sides.
Shutoff-opening devices are already known which comprise a rectangular parallelepipedal valve main body, and a plurality of valve actuators. Such a device is disposed at each of the inlet side and the outlet side of a massflow controller, or like controller, to provide a fluid control apparatus for use in semiconductor manufacturing equipment.
FIG. 17 shows a conventional shutoff-opening device 61. The device 61 comprises a rectangular parallelepipedal valve main body 63, and three valve actuators 64, 65, 66 mounted on the upper surface of the main body and arranged side by side longitudinally thereof (in the front-rear direction). The valve main body 63 is formed with a main channel 67 extending from the rear end face of the body 63 nearly to the front-end valve actuator 64, and three subchannels 68, 69, 70 communicating with the main channel 67 via the actuators 64, 65, 66, respectively. The upper surface of the valve body 63 is flat and parallel to the lower surface thereof. The actuators 64, 65, 66 are mounted on the flat surface, and spaced apart by equal distances.
When a fluid flows from the main channel 67 into the first subchannel 68, the dead volume (stagnant portion of fluid) of the device 61 is only short channels 71, 72 connecting the main channel 67 to the second and third actuators 65, 66. When the fluid flows from the main channel 67 into the second channel 69, the dead volume is the short subchannel 72 interconnecting the main channel 67 and the third valve actuator 66, and front end portions 67a, 67b of the main channel 67 positioned between the first valve actuator 64 and the second valve actuator 65. Further when the fluid flows from the main channel 67 into the third subchannel 70, the dead volume is the short channel 71 interconnecting the main channel 67 and the second valve actuator 65, the main channel front end portions 67a, 67b positioned between the first and second valve actuators 64, 65, and an intermediate portion 67c of the main channel 67 positioned between the second end third actuators 65, 66.
With the shutoff-opening devices and fluid control devices for use in semiconductor manufacturing equipment, it is critical to diminish the dead volume which reduces the purity of the process gas. It is also required that these devices be reduced in content volume, entire volume and weight, whereas the conventional devices still remain to be improved in these points.